America isn't better at integrating minorities than Europe because of geography but because of the fundamentals of how we were built. Taken nationalism for example. In Europe it is seen as a dangerous mindset that divides Europe and has led to some of your worst wars. In the US with the exception of some group think liberals nationalism is seen in very positive light and the lack of nationalism led to our worst war. We just view what makes a American different than how a Swede views what makes a Swede.

We do have large enclaves of immigrants that cluster in one area. Look at the various China Towns or even the large ethnic neighborhoods on the East Coast and in places like Chicago. We have huge neighborhoods that were at one time almost all Italian or Jewish or Irish ect. The biggest difference between America and just about everywhere else is there is no ethnic group that is considered "American". In the eyes of the vast majority of Americans you are just as American if your grandparents are from China as you are if the are from Scotland, as long as you ware willing to assimilate that is. Will the French ever consider a man of Ethiopian decent to be just as French as one whose ancestors fought with Napoleon?

That being said both of us our having trouble with Islamic immigrants. The US has it easier since we are not only better equipped than Europe to assimilate but I think we attract less radicalized Muslims than Europe does and many of the Muslims we have came here to get away from the very things that make it an issue. Of course any religion which believes its religious teachings supersede sectarian law will have trouble integrating. The hard truth of the matter is at this point in history many Muslims are just to radical in their beliefs to fit well in other nations. The US is large enough and diverse enough to absorb them and we are ruthless enough to force the issue if we have to. I am not sure that is true for many European nations.